term% cat index.txt IP(2) System Calls Manual IP(2)
NAME
eipfmt, parseip, parseipmask, v4parseip, v4parsecidr, parseether, myi‐
paddr, myetheraddr, maskip, equivip4, equivip6, ipcmp, defmask, isv4,
v4tov6, v6tov4, nhgetv, nhgetl, nhgets, hnputv, hnputl, hnputs, ptclb‐
sum, readipifc - Internet Protocol addressing
SYNOPSIS
#include <u.h>
#include <libc.h>
#include <ip.h>
int eipfmt(Fmt*)
vlong parseip(uchar *ipaddr, char *str)
vlong parseipmask(uchar *ipaddr, char *str)
char* v4parseip(uchar *ipaddr, char *str)
ulong v4parsecidr(uchar *addr, uchar *mask, char *str)
int parseether(uchar *eaddr, char *str)
int myetheraddr(uchar *eaddr, char *dev)
int myipaddr(uchar *ipaddr, char *net)
void maskip(uchar *from, uchar *mask, uchar *to)
int equivip4(uchar *ipaddr1, uchar *ipaddr2)
int equivip6(uchar *ipaddr1, uchar *ipaddr2)
int ipcmp(uchar *ipaddr1, uchar *ipaddr2)
uchar* defmask(uchar *ipaddr)
int isv4(uchar *ipaddr)
void v4tov6(uchar *ipv6, uchar *ipv4)
void v6tov4(uchar *ipv4, uchar *ipv6)
ushort nhgets(void *p)
uint nhgetl(void *p)
uvlong nhgetv(void *p)
void hnputs(void *p, ushort v)
void hnputl(void *p, uint v)
void hnputv(void *p, uvlong v)
ushort ptclbsum(uchar *a, int n)
Ipifc* readipifc(char *net, Ipifc *ifc, int index)
uchar IPv4bcast[IPaddrlen];
uchar IPv4allsys[IPaddrlen];
uchar IPv4allrouter[IPaddrlen];
uchar IPallbits[IPaddrlen];
uchar IPnoaddr[IPaddrlen];
uchar v4prefix[IPaddrlen];
DESCRIPTION
These routines are used by Internet Protocol (IP) programs to manipu‐
late IP and Ethernet addresses. Plan 9, by default, uses V6 format IP
addresses. Since V4 addresses fit into the V6 space, all IP addresses
can be represented. IP addresses are stored as a string of 16 unsigned
chars, Ethernet addresses as 6 unsigned chars. Either V4 or V6 string
representation can be used for IP addresses. For V4 addresses, the
representation can be (up to) 4 decimal integers from 0 to 255 sepa‐
rated by periods. For V6 addresses, the representation is (up to) 8
hex integers from 0x0 to 0xFFFF separated by colons. Strings of 0 in‐
tegers can be elided using two colons. For example, FFFF::1111 is
equivalent to FFFF:0:0:0:0:0:0:1111. The string representation for IP
masks is a superset of the address representation. It includes slash
notation that indicates the number of leading 1 bits in the mask.
Thus, a V4 class C mask can be represented as
FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FF00, 255.255.255.0, or /120. The
string representation of Ethernet addresses is exactly 12 hexadecimal
digits.
Eipfmt is a print(2) formatter for Ethernet (verb E) addresses, IP V6
(verb I) addresses, IP V4 (verb V) addresses, and IP V6 (verb M) masks.
Parseip converts a string pointed to by str to a 16-byte IP address
starting at ipaddr. As a concession to backwards compatibility, if the
string is a V4 address, the return value is an unsigned long integer
containing the big-endian V4 address. If not, the return value is 6.
Parseipmask converts a string pointed to by str to a 6-byte IP mask
starting at ipaddr. It too returns an unsigned long big-endian V4 ad‐
dress or 6. Both routines return -1 on errors.
V4parseip converts a string pointed to by str to a 4-byte V4 IP address
starting at ipaddr.
V4parsecidr converts a string of the form addr/mask, pointed to by str,
to a 4-byte V4 IP address starting at ipaddr and a 4-byte V4 IP mask
starting at mask.
Myipaddr returns the first valid IP address in the IP stack rooted at
net.
Parseether converts a string pointed to by str to a 6-byte Ethernet ad‐
dress starting at eaddr. Myetheraddr reads the Ethernet address string
from file dev/addr and parses it into eaddr. Both routines return a
negative number on errors.
Maskip places the bit-wise AND of the IP addresses pointed to by its
first two arguments into the buffer pointed to by the third.
Equivip returns non-zero if the IP addresses pointed to by its two ar‐
guments are equal. Equivip4 operates on v4 addresses, equivip6 oper‐
ates on v6 addresses. Ipcmp is a macro that compares V6 addresses per
memcmp(2)).
Defmask returns the standard class A, B, or C mask for ipaddr.
Isv4 returns non-zero if the V6 address is in the V4 space, that is, if
it starts with 0:0:0:0:0:0:FFFF. V4tov6 converts the 4-byte V4 ad‐
dress, v4ip, to a V6 address and puts the result in v6ip. V6tov4 con‐
verts the V6 address, v6ip, to a 4-byte V4 address and puts the result
in v4ip.
Hnputs, hnputl and hnputv are used to store 16-bit, 32-bit, and 64-bit
integers, respectively, into IP big-endian form. Nhgets, nhgetl and
nhgetv convert big-endian 2, 4 and 8 byte quantities into integers (or
uvlongs).
Pctlbsum returns the one's complement checksum used in IP protocols,
typically invoked as
hnputs(hdr->cksum, ~ptclbsum(data, len) & 0xffff);
A number of standard IP addresses in V6 format are also defined. They
are:
IPv4bcast
the V4 broadcast address
IPv4allsys
the V4 all systems multicast address
IPv4allrouter
the V4 all routers multicast address
IPallbits
the V6 all bits on address
IPnoaddr
the V6 null address, all zeros
v4prefix
the IP V6 prefix to all embedded V4 addresses
Readipifc returns information about a particular interface (index >= 0)
or all IP interfaces (index < 0) configured under a mount point net,
default /net. Each interface is described by one Ipifc structure which
in turn points to a linked list of Iplifc structures describing the ad‐
dresses assigned to this interface. If the list ifc is supplied, that
list is freed. Thus, subsequent calls can be used to free the list re‐
turned by the previous call. Ipifc is:
typedef struct Ipifc
{
Ipifc *next;
Iplifc *lifc; /* local addressses */
/* per ip interface */
int index; /* number of interface in ipifc dir */
char dev[64]; /* associated physical device */
int mtu; /* max transfer unit */
uchar sendra6; /* on == send router adv */
uchar recvra6; /* on == rcv router adv */
ulong pktin; /* packets read */
ulong pktout; /* packets written */
ulong errin; /* read errors */
ulong errout; /* write errors */
Ipv6rp rp; /* route advertisement params */
} Ipifc;
Iplifc is:
struct Iplifc
{
Iplifc *next;
uchar ip[IPaddrlen];
uchar mask[IPaddrlen];
uchar net[IPaddrlen]; /* ip & mask */
ulong preflt; /* preferred lifetime */
ulong validlt; /* valid lifetime */
};
Ipv6rp is:
struct Ipv6rp
{
int mflag;
int oflag;
int maxraint; /* max route adv interval */
int minraint; /* min route adv interval */
int linkmtu;
int reachtime;
int rxmitra;
int ttl;
int routerlt;
};
Dev contains the first 64 bytes of the device configured with this in‐
terface. Net is ip&mask if the network is multipoint or the remote ad‐
dress if the network is point to point.
SOURCE
/sys/src/libip
SEE ALSO
print(2), ip(3)
IP(2)